2TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, China; E-mail: email@example.com
3Department of General Microbiology, Institute of Microbiology, Biotechnology and Immunology, University of Lodz, PL 90-237 Lodz, Poland
4Tianjin Key Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin 300457, China
5Department of Immunobiology of Bacteria, Institute of Microbiology, Biotechnology and Immunology, University of Lodz, PL 90-237 Lodz, Poland
* To whom correspondence should be addressed.
Received February 14, 2012; Revision received February 21, 2012
A polysaccharide was isolated from the opportunistic human pathogen Providencia alcalifaciens O45:H26 by extraction with aqueous phenol and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including two-dimensional ROESY and H-detected 1H,13C HSQC experiments. The polysaccharide contains N-acetylglucosamine and N-acetylmuramic acid (d-GlcpNAc3Rlac) amidated with l-alanine and has the following structure:
The polysaccharide possesses a remarkable structural similarity to the bacterial cell wall peptidoglycan. It is not unique to the strain studied but is common to strains of at least four P. alcalifaciens O-serogroups (O3, O24, O38, and O45). No evidence was obtained that the polysaccharide is associated with the LPS, and hence it might represent a bacterial capsule component.
KEY WORDS: Providencia alcalifaciens, lipopolysaccharide, N-acetylmuramic acid, structure, bacterial polysaccharide, peptidoglycan